А*(12-а):2=а*6-½а=6а-½а=5½а
575:23=25
15*34=510
25+510=535
2884+1508= 4392
122-22=100
4392:100=43,92
34*25= 850
11*12= 132
850-132= 718
237-182= 55
55*23= 1265
1265-13=1252
5х+30+1=3-2х
5х+2х=3-30-1
7х=-28
х=-28/7
х=-4
(20,2 - 27 3/7) - y = 19 32/35
-у+20.2=19 32/35+27 3/7
-y+20.2=19 32/35+27 15/35
-y+20 1/5=47 12/35
-y=47 12/35-20 1/5
-y=47 12/35-20 7/35
-y=27 1/7
y=-27 1/7
x - 1,5 = - 1,8 - 11,2
х-1.5=-13
х=-13+1.5
х=-11.5
0,03 + x = 0,15 - 0,17
0.03+х=-0.02
х=-0.02-0.03
х=-0.05